This invention relates to a stable cosmetically elegant lotion, cream or foam oil in water emulsion useful as a topical anesthetic which exhibits no microscopic crystallization. The preparation is designed for relief of surface pain and itching and provides soothing temporary relief of minor burns, cuts, scratches, sunburn and other minor skin irritations.
The most common pain relieving agent used in topical anesthetic compositions is benzocaine. Since benzocaine is only very slightly soluble in water, solvents other than water have generally been used in benzocaine preparations, such as the polyethylene glycol esters taught in U.S. Pat. No. 3,322,624. Attempts to solubilize benzocaine in water using various surfaceactive agents have been made. However, the resulting preparations were generally found to be unstable with the benzocaine crystallizing or settling out, the problem being particularly acute at benzocaine concentrations over 0.5%.